This paper presents an extensive study of micro-scale fluctuations in the interplanetary medium, using data from Mariner V (Venus 1967). The key findings include: 1. Large amplitude, non-sinusoidal Alfvén waves dominate the micro-scale structure at least 50% of the time, with wavelengths ranging from 10^3 to 5 x 10^6 km. These waves often have energy densities comparable to both the unperturbed magnetic field and thermal energy densities. 2. Pure examples of outwardly propagating Alfvén waves occur in high-velocity solar wind streams and their trailing edges, where the velocity decreases slowly over time. In low-velocity regions, Alfvén waves are also outwardly propagating but are generally smaller in amplitude and more mixed with non-Alfvénic structures. 3. The largest amplitude Alfvénic fluctuations are found in compression regions at the leading edges of high-velocity streams, where the velocity increases rapidly. These regions may contain significant amounts of inwardly propagating or non-Alfvénic wave modes. 4. Power spectra of the interplanetary magnetic field show frequency dependencies of f^-1.5 to f^-2.2, with slower fall-offs associated with higher temperature regions. 5. Micro-scale magnetic field fluctuations exhibit a 5:4:1 power anisotropy in an orthogonal coordinate system, with the strongest anisotropy (6:3:1) in compression regions at the leading edges of high-velocity streams. 6. Magnetoacoustic wave modes are likely present but have small average power, and the eBxeR anisotropy is attributed to the partial conversion of Alfvén waves to damped magnetoacoustic modes as they are convected away from the sun. The observations are organized based on a model of the solar wind velocity structure, suggesting that most Alfvén waves are undamped remnants of waves generated near the sun. The high level of wave activity in high-velocity, high-temperature streams indicates extensive heating by wave damping near the sun. The highest level of Alfvénic wave activity in compression regions may be due to amplification of ambient waves or fresh wave generation during stream-stream collisions. The absence of magnetoacoustic modes suggests strong damping, and the anisotropy is explained by the conversion of Alfvén waves to damped magnetoacoustic modes.This paper presents an extensive study of micro-scale fluctuations in the interplanetary medium, using data from Mariner V (Venus 1967). The key findings include: 1. Large amplitude, non-sinusoidal Alfvén waves dominate the micro-scale structure at least 50% of the time, with wavelengths ranging from 10^3 to 5 x 10^6 km. These waves often have energy densities comparable to both the unperturbed magnetic field and thermal energy densities. 2. Pure examples of outwardly propagating Alfvén waves occur in high-velocity solar wind streams and their trailing edges, where the velocity decreases slowly over time. In low-velocity regions, Alfvén waves are also outwardly propagating but are generally smaller in amplitude and more mixed with non-Alfvénic structures. 3. The largest amplitude Alfvénic fluctuations are found in compression regions at the leading edges of high-velocity streams, where the velocity increases rapidly. These regions may contain significant amounts of inwardly propagating or non-Alfvénic wave modes. 4. Power spectra of the interplanetary magnetic field show frequency dependencies of f^-1.5 to f^-2.2, with slower fall-offs associated with higher temperature regions. 5. Micro-scale magnetic field fluctuations exhibit a 5:4:1 power anisotropy in an orthogonal coordinate system, with the strongest anisotropy (6:3:1) in compression regions at the leading edges of high-velocity streams. 6. Magnetoacoustic wave modes are likely present but have small average power, and the eBxeR anisotropy is attributed to the partial conversion of Alfvén waves to damped magnetoacoustic modes as they are convected away from the sun. The observations are organized based on a model of the solar wind velocity structure, suggesting that most Alfvén waves are undamped remnants of waves generated near the sun. The high level of wave activity in high-velocity, high-temperature streams indicates extensive heating by wave damping near the sun. The highest level of Alfvénic wave activity in compression regions may be due to amplification of ambient waves or fresh wave generation during stream-stream collisions. The absence of magnetoacoustic modes suggests strong damping, and the anisotropy is explained by the conversion of Alfvén waves to damped magnetoacoustic modes.